Longitudinal changes in calcaneal quantitative ultrasound measures during childhood

Summary This longitudinal study examined how calcaneal quantitative ultrasound (QUS) measures change during childhood while taking into account skeletalmaturation, bodymass index (BMI), and physical activity. The study reported sex differences in QUS growth curves and an inverse relationship between BMI and speed of sound (SOS) measures. Introduction The aim of this study was to examine how calcaneal QUS parameters change over time during childhood and to determine what factors influence these changes. Methods The study sample consisted of a total of 192 Caucasian children participating in the Fels Longitudinal Study. A total of 548 calcaneal broadband ultrasound attenuation (BUA) and SOS observations were obtained between the ages of 7.6 and 18 years. The best fitting growth curves were determined using statistical methods for linear mixed effect models. Results There are significant sex differences in the pattern of change in QUS parameters (p<0.05). The relationship between QUS measures and skeletal age is best described by a cubic growth curve in boys and a linear pattern among girls. Boys experience their most rapid growth in BUA and SOS in early and late adolescence, while girls experience constant growth throughout childhood. Adiposity levels were significantly associated with the changes in SOS among boys (p<0.001) and girls (p<0.01), indicating that children with higher BMI are likely to have lower SOS over time compared to children with lower BMI. For girls, physical activity levels showed positive associations with changes in QUS measures (p<0.05). Conclusion This study documents significant sex differences in the pattern of change in QUS measures over childhood and adolescence. Our study also shows significant influences of adiposity and physical activity on the pattern of change in QUS measures during childhood.